1. Field of the Invention
The present invention belongs to a liquid crystal panel processing field, relating to a measuring method for width of a color filter unit, more particularly, to the measuring method for width of the color filter unit by integrating a color filter plate into a liquid crystal panel on a thin film transistor (TFT) array substrate.
2. Description of the Prior Art
A liquid crystal display (LCD) is an ultra-thin plane display device, comprising a quantity of color or monochrome pixels, locating in front of light-source or reflection plane. Because of merits such as low power dissipation, high image quality, small volume and light weight etc., LCD is very popular and becomes mainstream of display devices. Conventional mainstream LCD is Thin Film Transistor (TFT), the major component of which is liquid crystal panel. There are two structure types of conventionally applied Liquid crystal panel: one is traditional liquid crystal panel comprising a thin film transistor array substrate and a color filter plate, the other integrates the color filter plate into the thin film transistor array substrate directly, i.e. a color filter on array (COA) liquid crystal panel. FIG. 1 indicates a COA liquid crystal panel comprising a upper glass substrate 10, a bottom glass substrate 20 and a liquid crystal layer 30 in between. A plurality of TFTs 201 are set up on one side of the bottom glass substrate 20 near the liquid crystal layer 30. Every TFT 201 is correspondingly connected to an electrode pixel 205 on which a transparent passivation layer is usually set up (not indicated in the figure). A color filter plate 203 is set up between the TFT 201 and the pixel electrode 205 due to COA application. The color filter plate 203 comprises a red filter unit 203R, a green filter unit 203G and a blue filter unit 203B, to each of which a pixel electrode 205 corresponds respectively. The TFT 201 and the color filter plate 203 are separated by a first insulating barrier 202, and the color filter plate 203 and the pixel electrode 205 are separated by a second insulating barrier 204. An array of black matrix 101 is set up on one side of the upper glass substrate 10 near the liquid crystal layer 30. Every black matrix 101 corresponds to pair wise zones between the filter units 203R, 203G and 203B to prevent light leaking. An ITO common electrode 102 covers the array of black matrixes 101.
In a liquid crystal panel with such the structure, the color filter plate 203 is manufactured on the TFT 201. While the liquid crystal panel is in processing, the color filter plate 203 is formed by photo etching process, the filter units 203R, 203G and 203B of three different colors are manufactured by three photo etching processes respectively in sequence. In order to prevent light leaking, two neighboring filter units 203R, 203G and 203B have to be connected tightly. As FIG. 2 indicates, for instance, the red filter unit 203R and the green filter unit 203G are connected tightly on interconnecting pieces and deposited on fringes, and the width of deposition is d1. As deposition on interconnecting pieces of two neighboring filter units, fringe of every filter unit 203R, 203G and 203B is beyond grab, resulting in inaccurate measuring of widths of the filter units 203R, 203G and 203B.